{"doi":"10.1103/physrevd.7.2333","title":"Black Holes and Entropy","abstract":"There are a number of similarities between black-hole physics and thermodynamics. Most striking is the similarity in the behaviors of black-hole area and of entropy: Both quantities tend to increase irreversibly. In this paper we make this similarity the basis of a thermodynamic approach to black-hole physics. After a brief review of the elements of the theory of information, we discuss black-hole physics from the point of view of information theory. We show that it is natural to introduce the concept of black-hole entropy as the measure of information about a black-hole interior which is inaccessible to an exterior observer. Considerations of simplicity and consistency, and dimensional arguments indicate that the black-hole entropy is equal to the ratio of the black-hole area to the square of the Planck length times a dimensionless constant of order unity. A different approach making use of the specific properties of Kerr black holes and of concepts from information theory leads to the same conclusion, and suggests a definite value for the constant. The physical content of the concept of black-hole entropy derives from the following generalized version of the second law: When common entropy goes down a black hole, the common entropy in the black-hole exterior plus the black-hole entropy never decreases. The validity of this version of the second law is supported by an argument from information theory as well as by several examples.","journal":"Physical Review D","year":1973,"id":1633,"datarank":25.372071653843975,"base_score":8.886409166849282,"endowment":8.886409166849282,"self_citation_contribution":1.3329613750273923,"citation_network_contribution":24.039110278816583,"self_endowment_contribution":1.3329613750273923,"citer_contribution":24.039110278816583,"corpus_percentile":96.2,"corpus_rank":1921,"citation_count":7232,"citer_count":194,"citers_with_citation_signal":194,"citers_with_endowment":194,"datacite_reuse_total":0,"is_dataset":false,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"1973-04-15","authors":[{"id":18749,"name":"Jacob D. Bekenstein","orcid":null,"position":0,"is_corresponding":true}],"reference_count":23,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-03-01T18:20:47.508186Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}